Silicon Application and Rhizobacterial Inoculation Regulate Mung Bean Response to Saline Water Irrigation

Abstract

The present investigation examined the effects of silicon application and inoculation with the plant growth-promoting rhizobacteria (PGPR) Enterobacter cloacae and Bacillus drentensis on alleviating ion toxicity, regulating osmolytes accumulation, and productivity of field-grown mung bean under saline water irrigation. Inoculated seeds were grown in sandy loam soils (electrical conductivity: 2.78 dS m À1 ) and irrigated with water with three salinity levels (3.12, 5.46, and 7.81 dS m À1 ) using a drip irrigation system. Foliar application of silicon was conducted twice (3 wk after sowing and at flowering stage) at 1 or 2 kg ha À1 . The silicon application and PGPR inoculation countered the adverse effects of salinity on mung bean by decreasing proline, total phenols, and lignin contents in leaves and increasing the total soluble sugars in comparison to the control. Silicon and rhizobacteria also reduced Na þ content and increased K þ , Ca 2þ , and Si contents in shoots compared to the control under all salinity levels. Furthermore, the significant interaction between Si and PGPR increased the pod yield. Among the treatments, Si (2 kg ha À1 ) application and B. drentensis inoculation remained the most prominent for the studied traits at all salinity levels. Thus, the current study suggested that application of rhizobacteria along with Si mitigates the effects of salinity on mung bean by regulating osmolytes, reducing lignification, improving mineral uptake, and decreasing tissue Na þ content.

Silicon-Mediated Physiological and Agronomic Responses of Maize to Drought Stress Imposed at the Vegetative and Reproductive Stages

“…In this study, drought stress resulted in a significant inhibition of transpiration rate and stomatal conductance, which corroborates previous reports in wheat and dry bean (Phaseolus spp.) [42]. However, Si fertilization strongly increased transpiration rate and stomatal conductance under drought stress imposed at the V12 and R2 stages.…”

Interactive Role of Silicon and Plant–Rhizobacteria Mitigating Abiotic Stresses: A New Approach for Sustainable Agriculture and Climate Change

“…PGPRs may enhance biological N 2 fixation, biosynthesis of phytohormones, and nutrient solubilization to sustain plant growth and development, with the ability to resist environmental stresses [ 44 ] ( Figure 1 and Figure 2 , Table 1 and Table 2 ). The pioneering work related with synergistic action and an improved technique for the mitigation of saline stress in Vigna radiata though combinatorial application of Si and PGPRs was studied [ 45 , 48 ]. In this section, the mechanisms and functions of PGPRs and Si-mediated stress tolerance in agricultural crop plants are discussed.…”

Silicon improves rice nutrition and productivity under salinity

“…Recently, Si has been reported to reduce the impacts of various abiotic stresses like heat, drought, heavy metals and salinity on plants (Ashraf et al, 2010;Jang et al, 2018). The role of Si in alleviating salinity stress has been observed in wheat (Tahir et al, 2006), rice (Kim et al, 2014;Tahir et al, 2018) and mung bean (Mahmood et al, 2016(Mahmood et al, , 2017. However, mechanisms by which Si alleviates salinity stress in plants are yet to be established.…”